Urethane resins

ABSTRACT

Amine-terminated urethane oligomer compositions are described that include very high oligomer concentrations. The compositions are melts of the amine-terminated oligomers. The compositions can include one or more property modifiers. The compositions are useful in the formation of crosslinked copolymers, especially with epoxy resins. The resulting copolymers are useful in the formation of coatings.

FIELD OF THE INVENTION

[0001] The invention relates to compositions comprising urethane resins,in particular, amine-terminated urethane oligomers. The inventionfurther relates to polymers prepared by combining urethane oligomerswith crosslinking agents and to coatings formed from the resultingpolymers

BACKGROUND OF THE INVENTION

[0002] Polyurethanes are used in a variety of commercial applicationsfor the production of products such as fibers, adhesives, coatings,elastomers and foams. Polyurethane coatings can have desirableproperties including high gloss, chemical resistance and abrasionresistance. Preferred urethane coatings also display flexibility, impactresistance, and toughness. For use as coatings, the composition must beprepared in a form that can be spread on the relevant surface The curingor crosslinking Process then completes polymer formation as anyremaining volatiles evaporate.

[0003] Urethane coatings can be supplied in the form of a two componentformulation, where the two components are mixed prior to application toa surface One component includes urethane oligomers with suitablefunctional groups available for crosslinking. The second componentincludes a crosslinking agent that can react with the functional groupsof the urethane oligomers

SUMMARY OF THE INVENTION

[0004] The present invention involves the formation of compositions withvery high concentrations of amine-terminated urethane oligomers Theoligomers of compositions generally are unsolvated. The compositions caninclude plasticizers, viscosity modifiers and other additives. Thecompositions generally have sufficiently low viscosities such that theycan be blended with appropriate crosslinking compositions to formdesirable polymers. The high solid, urethane oligomer compositions haveimproved properties for the formation of coatings. In particular, thepolymer compositions can be applied in relatively thick layers withouthindering the curing process to form high quality coatings.

[0005] In a first aspect, the invention features a composition includinggreater than about 55 percent by weight amine-terminated urethaneoligomers. In selected embodiments the composition includes from about60 percent to about 90 percent by weight amine-terminated urethaneoligomers. In other embodiments the composition includes from about 65percent to about 80 percent by weight amine-terminated urethaneoligomers.

[0006] The composition can further include an aqueous viscositymodifying agent. The aqueous viscosity modifying agent can includegreater than about 30 percent by weight volatile alcohol. Thecomposition also can include volatile organic acids, with thecomposition preferably comprising less than about 10 percent and morepreferably less than about 1 percent by mole equivalent of carboxylategroups of the volatile organic acids relative to amine groups of theamine-terminated urethane oligomers. The amine-terminated urethaneoligomers can include primary amine-terminated oligomers. Theamine-terminated urethane oligomers can include multifunctional aminemoieties bonded at secondary amine sites to isocyanate functional groupsof a urethane oligomer to form carbamate linkages. Suitablemultifunctional amine moieties include N-(aminoethyl) piperazinemoieties.

[0007] In another aspect, the invention features a kit including:

[0008] a) a composition comprising greater than about 55 percent byweight amine-terminated urethane oligomers; and

[0009] b) a polyepoxide compound in a container separate from thecomposition comprising amine-terminated urethane oligomers.

[0010] The polyepoxide can be a polyglycidyl ether of a polyphenol, apolyglycidyl ether of aliphatic polyol with 2 to 4 hydroxyl groups, ormixtures thereof. The ratio of active hydrogens in amine functionalgroups to epoxide groups preferably ranges from about 1:1 to about1.75:1.

[0011] In another aspect, the invention features a method of producingan amine-terminated urethane oligomer composition comprising the stepsof

[0012] a) adding water to a polyketimine functionalized urethaneoligomer; and

[0013] b) removing ketone to form a composition comprising greater thanabout 55 percent by weight amine-terminated urethane oligomer.

[0014] In another aspect, the invention features a polymer coatingincluding an epoxy crosslinked amine-terminated urethane polymer, thecoating being formed by curing a mixture of polyepoxides and acomposition comprising greater than about 55 percent by weightamine-terminated urethane oligomers.

[0015] In another aspect, the invention features a method of forming acoating comprising the steps of spreading a mixture on a surface suchthat it can cure, the mixture obtained by mixing polyepoxides with acomposition comprising greater than about 55 percent by weightamine-terminated urethane oligomers. The surface can be concrete and canform a wall or a floor.

[0016] Other features and advantages of the invention follow from thedetailed description of the invention and claims below.

DETAILED DESCRIPTION

[0017] Novel compositions include surprisingly high proportions ofamine-terminated urethane oligomers while generally exhibiting suitableTheological properties. Amine-terminated urethane oligomers have aminefunctional groups available for further reaction with, for example, acrosslinking agent. The novel compositions generally are roomtemperature “melts” (i.e., flowable polymer compositions where thepolymer is not dissolved in a solvent) that may include viscositymodifiers to reduce the viscosity for easier handling. Some of thesecompositions have qualitatively different properties than compositionsinvolving aqueous emulsions of amine-terminated urethane oligomers. Theimproved compositions have excellent properties conducive to theformation of coatings upon mixing with a crosslinking agent.

[0018] The formation of the amine-terminated urethane oligomers firstinvolves generation of an isocyanate functional urethane oligomer by thereaction of a polyisocyanate compound with a compound having activehydrogens such as a polyol, an amine or a thiol. The isocyanatefunctional urethane oligomer is then reacted with a compound having asingle active hydrogen and at least one protected primary amine group.The protected amine group generally involves a ketimine formed byreacting a ketone with the primary amine. After completing formation ofthe ketimine terminated urethane oligomer, the ketimine can behydrolyzed to form the amine-terminated urethane oligomer.

[0019] The amine-terminated urethane oligomers can-be crosslinked at theamine functional groups to form polymers. Preferred crosslinking agentsinclude epoxy resins and acrylates. The resulting polymer can have theadvantageous properties of a polyurethane together with other propertiescontributed by the crosslinking agent.

[0020] An amine-terminated urethane oligomer composition has severaladvantages over compositions with corresponding oligomers in aqueousemulsions. For example, the higher solid concentration means that asmaller volume is required to hold an equivalent amount of oligomer.Furthermore, significant quantities of volatile organic acids used toform the aqueous emulsion are not needed. The volatile organic acidsslow the curing process since they must evaporate to permit thecrosslinking reaction to proceed. In addition, thicker layers of thehigh solid material can be formed in a single application of the coatingsince bubble formation from the evaporation of organic acid and water isless of a concern.

[0021] A. Formation of Urethane Oligomers

[0022] First, an isocyanate terminated urethane oligomer is formed. Thisstep can be carried out conventionally through reaction ofpolyisocyanates, especially diisocyanates and triisocyanates, withpolyfunctional organic compounds having at least two active hydrogenatoms for reaction with the isocyanate functional groups In general, theisocyanate functional groups should be in excess relative to the activehydrogen functional groups. The ratio of isocyanate functional groups toactive hydrogen atoms preferably is from about 1.01:1 to about 5:1, andmore preferably from about 1.1:1 to about 3:1.

[0023] Representative polyisocyanates include, for-example, toluenediisocyanate, 4, 4′-diphenyl diisocyanate, 4,4′- diphenylmethanediisocyanate, 4, 4′-diphenyl-ether diisocyanate, dianisidinediisocyanate, 1, 5-naphthalene diisocyanate, p-phenylene diisocyanate,trimethylene diisocyanate, octadecylmethylene diisocyanate,2-chloropropane diisocyanate, 4, 4′-methylene-bis(phenyl isocyanate),isophorone diisocyanate, 1, 5-hexamethylene diisocyanate, 4,4′-methylene-bis(cyclohexyl isocyanate), 4, 4′, 4″-triphenyl-methanetriisocyanate, 1, 3, 5-benzene triisocyanate, polymethylene poly(phenylisocyanate), and mixtures thereof. Suitable polyisocyanates also includebiurets such as the biuret of 1,6-hexamethylene diisocyanate sold asTolanate HDB™ (Rhone-Poulenc, Shelton, Conn.) and isocyanurates such asthe isocyanurate of 1,6-hexamethylene diisocyanates sold as TolanateHDT™ (Rhone-Poulenc, Shelton, Conn.).

[0024] A variety of organic compounds have at least two active hydrogenatoms that are reactive with free isocyanate groups, includingpolyfunctional mercaptans, primary and secondary amines, carboxylicacids, alcohols and combinations thereof. Suitable poly-secondary aminesinclude, for example, piperazine. Preferred polyols have a molecularweight from about 200 to about 7500. Suitable polyols include, forexample, ethylene glycol, diethylene glycol, 1, 3-propylene glycol,1,4-butane diol, glycerol, trimethylol-propane, erythritol,pentaerythritol, polyethers such as poly(ethylene oxide) diol andpoly(propylene oxide) diol, polylactones such as polycaprolactone, andpolyhydroxypolyesters of polycarboxylic acids such as esters of succinicacid, adipic acid, azelaic acid, sebacic acid, phthalic acid,isophthalic acid, and teraphthalic acid with polyols such as ethyleneglycol, diethylene glycol, 1,4-butane diol, trimethylolpropane,glycerol, erythritol, pentaerythritol, poly(ethylene oxide) diol,polyethyleneoxide/propylene oxide) diol, and poly(tetramethylene oxide)diol.

[0025] Suitable urethane oligomers can be formed with pure polyols,especially diols. Nevertheless, it can be advantageous to add a mixtureof diols and triols. The incorporation of triols provides a morebranched structure. When a mixture of diols and triols is used, theratio of triols to diols preferably is from 0.05:1 to about 2:1 and morepreferably from about 0.1:1 to about 1.25:1.

[0026] Preparation of the isocyanate functional polyurethane oligomerscan be accomplished by a one-stage process. In this process, thereactants including at least one polyisocyanate compound and at leastone polyol are mixed to initiate the reaction. The reaction can becarried out under anhydrous conditions at a temperature from about 50°C. to about 80° C. for several hours. The reaction to form theisocyanate functional polyurethane can be carried out in a melt or insolution. In other words, an inert organic solvent optionally can beadded when forming the reaction mixture. Suitable organic solventsinclude, for example, methyl acetate, ethyl acetate, amyl acetate,acetone, methyl ethyl ketone, diethyl ketone, methylisobutyl ketone,dimethyl formamide, dioxane, and methyl pyrrolidone.

[0027] B. Amine-Terminated Urethane Oligomers

[0028] The isocyanate functional urethane oligomers can be reacted withat least one ketimine or polyketimine to form ketimine functionalpolyurethane oligomers. The ketimine and polyketimines can be formed byreacting primary amines with a ketone as a removable protecting group.Ketones enter into a condensation reaction with the primary amine, wherethe carbonyl of the ketone combines with the-two active hydrogens of theprimary amine group to form water and a ketimine If the correspondingunprotected primary amines are reacted with the isocyanate functionalpolyurethanes, crosslinking occurs due to reaction of the amine groupswith the isocyanates, which can result in gelation if sufficientcrosslinking takes place.

[0029] Appropriate mono- or poly- primary amines have another reactivehydrogen that does not react with the ketone, for example a secondaryamine, a hydroxyl or a thiol group. In other words, the primary aminecan be a monosecondary amino, monohydroxy, or monothio substituted,mono- or polyfunctional primary amine. The ketimine has the generalformula:

H—X—R₁ (N=R₂)_(n),

[0030] where n is at least one and where X can be O (hydroxyl), NR₃(secondary amine) or S (thiol). R₂ is the residue of the ketone that isformed into the ketimine. R₁ can be an aliphatic, cycloaliphatic,heterocyclic or aromatic hydrocarbon moiety, and may be saturated orunsaturated. R₁ can be extensively branched and can bear one or moreadditional ketimine functional groups. R₁ contains preferably 2-8 carbonatoms and more preferably 2-4 carbon atoms R₃ can be an aliphatic,cycloaliphatic, heterocyclic or aromatic hydrocarbon moiety, and can besaturated or unsaturated. R₃ can be bonded to R₁ to form a heterocyclicstructure. R₃ contains preferably 1-8 carbon atoms and more preferably1-4 carbon atoms.

[0031] There are few examples of commercially available monosecondaryamino, monoprimary amines. Suitable commercially available compoundsinclude, for example, N-(ω-aminoalkyl)-substituted diazacyloalkanes oralkenes such as N-(aminoethyl)piperazine and N-alkyl-1,ω-diaminoalkanessuch as N-methyl-1,3-propanediamine. Similarly, commercially-availablemonosecondary amino, polyfunctional primary amines are likewise few innumber. Two examples of commercially available compounds containing twoprimary amine groups and one secondary amine group are diethylenetriamine (D. E. H. 20™, Dow Chemical, Midland, Mich.) andbis(hexamethylene)triamine (DuPont, Wilmington, Del.).

[0032] Examples of suitable monohydroxy, monoprimary amines include, forexample, monoethanolamine, monoisopropanol amine, and3-amino-1-propanol. Suitable monohydroxy, polyfunctional primary aminesinclude, for example, 1,3-diamino-2-hydroxypropane. Monothio-, mono- orpolyfunctional primary amines can be prepared by the reaction ofhydrogen sulfide or certain mercaptans with unsaturated monoamines suchas alkyl amines including, for example, butenyl amines and cyclohexenylamine. Examples of useful mercaptans for these syntheses include, forexample, 1,3 propanedithiol, 1,4 butanedithiol, and 1,4 benzenedithiol.

[0033] Suitable ketones for forming the ketimine include, for example,acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone,dibutyl ketone, diisobutyl ketone, methyl isopropyl ketone, methyl octylketone, ethyl butyl ketone, and dioctyl ketone. The ketimines orpolyketimines can be prepared, for example, according to the methodsdisclosed in U.S. Pat. No. 3,291,775 or as described in the examplesbelow.

[0034] Note that the product water can be removed, for example byevaporation, to increase the formation of ketimine. If the water is notremoved, a proportion of the primary amine remains unprotected. Thisunprotected primary amine along with the additional reactive hydrogen inthe molecule can react with isocyanate groups to crosslink the urethaneoligomers. Generally, reaction with the primary amines results in alower crosslinking density since amide formation can prevent fullcrosslinking with both active hydrogens of the primary amine. As notedbelow, crosslinking density affects the properties of the resultingpolymer and coating formed from the polymer. On the other hand, theprimary amines react quickly with the isocyanate groups such that thematerial very quickly can become too viscous to handle easily if theprimary amine concentration is too high. Nevertheless, since the ketonecan be present in a large excess, the presence of product water may notresult in a sufficiently large quantity of free primary amine tosignificantly crosslink the urethane oligomers.

[0035] The ketimines or polyketimines are reacted with the isocyanatefunctional urethane oligomers to form ketimine functional urethaneoligomers. The active hydrogen associated with the X-H group of theketimine or polyketimine reacts with an isocyanate functional group Theresulting compounds are ketimine or polyketimine terminated urethaneoligomers represented by the formula:

R—(NHCOX—R₁ (N=R₂)_(n))_(m),

[0036] where R is the urethane oligomer backbone and m is the number ofisocyanate functional groups in the original urethane oligomer X, R₁, R₂and n are defined above.

[0037] Generally, approximately one equivalent of ketimine compositionis added per isocyanate (NCO) equivalent of urethane oligomer. If theratios of equivalents are not one-to-one, there may be unreactedisocyanates or active hydrogen groups that contribute to any latercrosslinking reaction, resulting in an overall reduction in crosslinkingdensity. Preferably, the ratio of equivalents of ketimine to NCO rangesfrom about 0.7 to about 1.3, and more preferably from about 0.8 to about1.2.

[0038] To complete formation of the primary amine-terminated urethaneoligomers, the ketone protecting groups are removed by hydrolyzing theketimine. One way of accomplishing this hydrolysis is though addition ofexcess water and a volatile organic acid. Addition of excess water and avolatile organic acid results in formation of an aqueous dispersion ofthe amine-terminated urethane oligomers. The organic acid is used toprotonate the amine groups to assist with the dispersion of the compoundin water.

[0039] It has been discovered that a second way can be used to performthe hydrolysis. In this second approach, a smaller amount of water canbe added to the ketimine terminated urethane oligomers. The smalleramount water hydrolyzes the ketimine to form the primary amine withoutformation of an aqueous dispersion. The resulting amine-terminatedurethane oligomer has the formula:

R—(NHCOX—R₁ (NH₂)_(n))_(m),

[0040] where R, R₁, R₂, X, n and m are defined above. Since theresulting compound is not dispersed in water, a smaller quantity ofvolatile organic acid can be added as a viscosity modifier. Similarly,no organic acid can be added.

[0041] Following hydrolysis of the ketimine, the ketone is evaporated toyield a “melt” of the oligomer. In this way, a composition can be formedwith very high proportions of amine-terminated urethane oligomers. Afterremoval of the ketone, the composition generally comprises greater thanabout 55 percent by weight of the amine-terminated urethane oligomers,preferably from about 65 percent by weight to about 90 percent by weightand more preferably from about 70 percent by weight to about 80 percentby weight.

[0042] The added water can include miscible organic components thatfunction as viscosity modifying agents. For example, a quantity ofvolatile organic acids, optionally, can be added. The compositiongenerally includes less than about 10 percent, preferably less thanabout 1 percent, by mole equivalent of carboxylate groups of thevolatile organic acids relative to all the amine groups (primary,secondary and tertiary) found in the amine-terminated urethaneoligomers. Suitable organic acids include, for example, acetic acid.Other suitable miscible organic components include, for example,alcohols such as benzyl alcohol, n-butanol and isopropyl alcohol. Whenmethyl ethyl ketone is used as the ketone protecting group, isopropylalcohol is preferred since isopropyl alcohol forms an azeotrope withmethyl ethyl ketone that assists with the removal of the ketone.

[0043] Effectively all or most of the ketone generally is removed fromthe composition since residual ketone can interfere with the eventualcrosslinking reaction, although a small amount of ketone does notinhibit significantly the eventual crosslinking reaction. The finalcomposition includes the amine-terminated urethane oligomer, anyunreacted and unevaporated water, and any unevaporated organic solvent.The remaining water and organic solvent such as alcohol can act asplasticizers and/or viscosity modifiers. While the resultingamine-terminated urethane oligomer compositions have high viscosities,they are flowable. Therefore, they can be combined with a crosslinkingagent to form a crosslinked polymer. Additional processing aids such asplasticizers and viscosity modifiers can be added to modify theproperties of the composition. Similarly, additional additives can beadded to a second component that is combined with the urethane oligomersto form a copolymer.

[0044] C. Crosslinked Urethanes (Copolymers)

[0045] The amine-terminated urethane oligomers can be reacted with acrosslinking agent to form a copolymer. Suitable crosslinking agentsinclude, for example, monomers or oligomers with epoxy or acrylatefunctional groups. Suitable acrylate crosslinking agents include, forexample, trimethylol propane triacrylate (TMPTA) and urethane acrylates.Epoxy based crosslinking agents are of particular interest.

[0046] Epoxy resins of interest contain at least one, but preferablymore than one, 1,2-epoxy group of the formula:

[0047] Suitable epoxy resins can be saturated or unsaturated, aliphatic,cycloaliphatic, aromatic, or heterocyclic. The epoxy resins have anaverage molecular weight preferably from about 100 to about 2000 andmore preferably from about 140 to about 200. A selected epoxy resin canbe supplied in the form of a solution in an organic solvent, water, or acombination of water and a water miscible organic solvent.Alternatively, the epoxy resin can be supplied in an unsolvated form,substantially free of organic solvent and water.

[0048] Examples of suitable epoxy resins include, for example,polyepoxides containing pendant and/or terminal 1,2-epoxy groups, suchas the polyglycidyl ethers of polyphenols. Polyglycidyl ethers ofpolyphenols may be prepared, for example, by etherification of apolyphenol with epichlorohydrin or dichlorohydrin in the presence ofbase. Examples of suitable polyphenols include1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane,1,1-bis(4-hydroxyphenyl) isobutane, 2,2-bis(4-hydroxy-t-butylphenyl)propane, bis(2-hydroxy-1,5-dihydroxy) naphthalene,1,1-bis(4-hydroxy-3-allyphenyl)ethane, and hydrogenated derivativesthereof. The polyglycidyl ethers of polyphenols of various molecularweights can be produced, for example, by varying the molar ratio ofepichlorohydrin to polyphenol.

[0049] Useful polyepoxides also include, for example, the polyglycidylethers of mononuclear polyhydric phenols such as the polyglycidyl ethersof rescinol, pyrogallol, hydroquinone and pyrocatechol. Suitable epoxyresins also include the polyglycidyl ethers of polyhydric alcohols suchas the reaction products of epchlorohydrin or dichlorohydrin with(C₂-C₂₀) aliphatic or cycloaliphatic compounds containing from two tofour hydroxyl groups including, for example, ethylene glycol, diethyleneglycol, triethylene glycol, dipropylene glycol, tripropylene glycol,propane diols, pentane diols, glycerol, 1,2-hexanetriol, pentaerythritoland 2,2-bis(4-hydroxy cyclohexyl) propane.

[0050] Suitable epoxy resins also include aliphatic, cycloaliphatic andglycidyl ether type 1,2-epoxides such as propylene oxide, styrene oxide,vinylcyclohexene dioxide, glycidol, butadiene oxide, glycidylpropionate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate,bis-(3,4-epoxy-6-methyl cyclohexyl methyl)adipate, dipentene oxide andpoly(dimethylsiloxanes) having cycloaliphatic epoxide or glycidyl ethergroups. Suitable polyepoxides additionally include polyglycidyl estersof polycarboxylic acids. Examples of which include polyglycidyl estersof bis(carboxylic acids such as adipic acid, phthalic acid and the like.

[0051] Polymerized resins containing epoxy groups can also be used.These polyepoxides can be produced by addition polymerization of epoxyfunctional monomers such as glycidyl acrylate, glycidyl methacrylate,and allyl glycidyl ether, optionally in combination with ethylenicallyunsaturated monomers such as styrene, alpha-methyl styrene, alpha-ethylstyrene, vinyl toluene, t-butyl styrene, acrylamide, methylacrylamide,acrylonitrile, methacrylonitrile, ethyl methacrylate, isobutylmethacrylate, isopropyl methacrylate, isobutyl methacrylate andisobornyl methacrylate. Many additional examples of useful epoxy resinsare described in the Handbook of Epoxy Resins, H. Lee et al., eds.,McGraw Hill Book Company (1967).

[0052] Stoichiometric blends of epoxy resins and active hydrogen bearingcuring agents do not necessarily provide optimal polymer properties,especially for use as coatings. The ratio of 1,2-oxirane (epoxide)equivalency to active hydrogen equivalency from the primary amines ofthe urethane oligomers can be varied widely, and the resulting coatingsexhibit a wide range of physical property differences. Note that eachprimary amine functional group is difunctional and capable ofinteracting with two epoxide groups. The ratio of 1,2-oxiraneequivalency to active hydrogen equivalency can be varied from about1:0.5 to 1:2 or higher.

[0053] Infrared analysis has shown that a slight excess of activehydrogen equivalency (about 0.9 equivalents of epoxide peractive-hydrogen atom) is required to obtain complete disappearance ofabsorbance due to the 1,2-oxirane group. Active hydrogen equivalency canbe evaluated using a direct measure of isocyanate equivalency and atheoretical estimate based on the amount of ketimine/primary amine addedto form the ketimine functionalized urethane oligomers. The quantitiesof active-hydrogen atoms necessary to obtain complete disappearance ofthe 1,2-oxirane functionality can be referred to as the “optimal”quantity. At “optimum” blend ratios, the polymeric coating is nearlycompletely cross-linked.

[0054] As the ratio of active hydrogen atoms is increased above optimum,some of the active hydrogen atoms do not react with the epoxide groups.Excess active hydrogen atoms result in a degree of linearity, in otherwords a reduction in the cross-linking density in the cured polymer.Increasing the amount of amine active hydrogens above the level found toreact with all of the 1,2-oxirane groups can provide a polymer withincreased flexibility and decreased hardness and brittleness. Otherproperties can deteriorate if the mix ratio of the oligomer componentsare not selected properly. For example, tensile strength can droprapidly while water, chemical and abrasion resistance can be reduced.These property differences may be due to molecular configurations in thecured polymer that vary according to the amount of the excess activehydrogen atoms. As noted above, crosslinking of isocyanate groups byunprotected primary amine combined with the ketimine also can result ina reduced crosslinking density.

[0055] Consequently, the characteristics of the oligomers and theirratios can be manipulated to produce desired properties. Typicalpolyurethane properties can be built into the urethane oligomer. Largerurethane oligomers with slight to moderate branching are preferred.Reduced branching of the urethane oligomers generally results in a morepliable coating. Urethane oligomers preferably have an average molecularweight from about 400 to about 1200. The polyurethane-like character canbe enhanced by restricting the amount of epoxide oligomer curing agentby using a lower molecular weight epoxy.

[0056] If a suitable urethane oligomer is selected, the physicalproperties of the urethane/epoxy copolymer do not degrade as the activehydrogen atom/epoxide ratio exceeds stoichiometric, i.e., “optimal,”values. The urethane-like properties of high abrasion resistance andgloss retention are generally observed at blending ratios of 1.25-1.75active hydrogen equivalents per epoxide. In certain cases, propertiescontinue to improve as the active hydrogen equivalent per epoxide ratiois increased to 2:1. When active hydrogen per epoxide ratios are withinthe range of 1.25-1.75, the copolymer formed with larger urethaneoligomers exhibits water resistance typical of films obtained withessentially stoichiometric blends. The water resistance of the curedpolymers starts to decline as the active hydrogen atom/epoxide ratioapproaches and exceeds 2:1.

[0057] Urethane-epoxy blends generally exhibit a limited pot life of afew minutes to several hours after combining the components, for film orcoating formation. Pot life has been associated with an increase inviscosity due to formation of the copolymer. When the viscosity hasincreased to the point that application becomes difficult and adversefilm appearance characteristics cannot be avoided, the effective potlife of the blend is considered exceeded.

[0058] For optimal cure conditions, the urethane oligomer compositionand epoxy resin should be between about 60° F. and about 100° F., andmore preferably between about 70° F. and about 90° F. Premeasuredquantities of the urethane oligomer composition and the epoxy resin canbe poured into a clean container and blended thoroughly, for example,using a power mixing paddle or agitator, such as a Jiffy Mixer(distributed by Jiffy Mixer Company, Inc., San Francisco, Calif.) usinga high strength industrial drill at low speed for a minimum of 5minutes. Following mixing, the polymer is ready for the formation ofcoatings and the like.

[0059] D. Packaging and Distribution

[0060] Generally, the amine-terminated urethane oligomers and epoxyresins or other crosslinking composition are packaged and stored inseparate containers awaiting use. Due to limited pot life, the twocomponents of the copolymer are generally mixed at the site for curingof the copolymer. For distribution, the amine-terminated urethaneoligomers and the epoxy resins preferably are packaged in containerswith premeasured quantities suitable for mixing. In other words, thecontents of the urethane oligomer container are mixed with the contentsof the epoxy resin container to form a copolymer mixture with desiredcharacteristics. This packaging in suitably measured quantities providesfor easy preparation of the crosslinked copolymer without the need forthe end user to measure desired amounts of the components of thecopolymer.

[0061] The two premeasured components can be placed in a single package,such as a box or different portions of a divided package, fordistribution. Alternatively, the different containers can be shipped inseparate packaging along with a instruction label indicating that onecontainer is to be mixed with the contents of the other container.

[0062] E. Coatings

[0063] The urethane/epoxy copolymers described above are particularlyuseful for the formation of coatings. The copolymers are preferablycured at ambient temperatures following application to a substrate.Alternatively, films of the blends can be heated to speed thecrosslinking process. To form the coating, the two components of thecopolymer generally are mixed, stirred and spread. Preferred substratesinclude concrete and wood surfaces such as floors and walls.

[0064] To form a floor coating, for example, the blend can be appliedusing a roller from a pan, or poured onto the floor in a windrow fashionand leveled using a squeegee. The coating can be spread, for exampleusing a notched squeegee. Alternatively, the copolymer can be spreadusing a screen box to apply the material at a desired thickness over thesubstrate. The spread copolymer can be backrolled with a nap roller, ifdesired, to smooth any imperfections. The copolymer can be mixed withsand or the like to form a mortar prior to application to a surface.

[0065] Due to the high solids concentrations, i.e. low solventconcentrations, the present urethane/epoxy mixtures generally can beapplied at greater thicknesses without adversely affecting the curingproperties. In particular, the urethane oligomer/epoxy oligomer blendscan be applied to a surface at a thickness of greater than about 1 mil,preferably from about 2 mils to about 200 mils. Thicker systems tend tobe applied as mortar to repair eroded concrete.

[0066] Since a relatively large amount of volatile organic acid is notused to form a water emulsion, the curing rate does not depend on therate of evaporation of the volatile organic acid. Generally, even whenapplied at relatively large thicknesses, the urethane/epoxy copolymerare dry to the touch within about 24 hours to about 48 hours. Generally,two weeks are required for complete curing of epoxies.

[0067] F. Coating Properties

[0068] While the properties of the final copolymers are influenced bythe crosslinking agent, the urethane components have a significantinfluence on the properties of the resulting copolymer. Perhaps thepredominant performance feature of polyurethane coatings thatdistinguishes them from other industrial/architectural coatings is their“toughness.” The Paint/Coatings Dictionary, published by the Federationof Societies for Coatings Technology, 1978, defines toughness as “thatproperty of a material by virtue of which it can absorb work.” “Brittle”is defined in the same dictionary as “the opposite of tough.” Abrasionresistance is a commonly measured property in the protective coatingsindustry and is closely related to toughness since it measures the workabsorbing capacity of a coating. If desired, toughness can be defined asthe abrasion resistance.

[0069] Various of techniques to evaluate abrasion resistance ofprotective coatings are published by ASTM. ASTM Method D-4060-81,“Abrasion Resistance of Organic Coatings by the Taber Abraser,” isperhaps the most widely used Abrasion resistance is determined by thistest in terms of milligrams (mg) of coating loss per 1000 cycles of wearas applied by a Taber Abraser. A lower value of mgs of coating lostgenerally indicates a greater ability of the protective coating toresist abrasion.

[0070] It should be noted, however, that coatings that are very soft andextensible, but yet resilient, can yield low abrasion resistant values,indicative of good abrasion resistance, under the ASTM D-4060-81 testwhile the coatings are too soft to be useful as protective coatings formany applications. Thus, depending on the overall performancerequirements of the coating system, a coating with the lowest abrasionresistance values under the ASTM D-4060-81 test may not have desiredperformance characteristics Therefore, it is useful to combinemeasurements of abrasion resistance under the ASTM D-4060-81 test withmeasurements such as tensile strength and hardness. A coating productintended for use as an industrial floor coating must have sufficienttensile or cohesive strength to resist scratching, and sufficienthardness to resist dirt collection from industrial traffic.

[0071] Film hardness can be evaluated in accord with ASTM MethodD-4366-84, “Hardness of Organic Coatings by Pendulum Damping Tests.”ASTM D-4366-84 describes the use of a König hardness tester. ASTMD-4366-84 is a preferred hardness test since surface imperfections havelittle influence on the resulting hardness measurements under ASTMD-4366-84, “König hardness” is defined as the “time in seconds for theswing of the König pendulum to decrease from 6° to 3°. “The Könighardness tester is calibrated on plate glass to yield a value of 250±10seconds.

[0072] Tensile strength and elongation can be measured following theprocedures found in ASTM D 2370-92. For the tests, a copolymer film isproduced as a free film with a uniform thickness. The free film isformed by casting the copolymer onto a non-stick plastic board. Atensile tester from Instron (Canton, Mass.) is used. After completelydrying, the substrate is removed from the board. The copolymer film iscut to the dimensions specified in the protocol and is placed in thejaws of the tensile tester. The tensile tester was set to have anelongation rate of 2 inches per minute. The film was elongated untilrupture of the film. The tensile strength was determined first by thestress in pounds per square inch (cross sectional area) required toreach the yield point where the elongation as a function of stressreaches a maximum and second by the stress required to rupture the film.Urethane films tend to stretch prior to breaking in contrast with epoxyfilms that are more brittle. Elongation was determined as the percentelongation at the breaking point.

[0073] For the measurements reported in the examples below, abrasionresistance was measured following ASTM D-4060-81 using a Taber Abraser,König hardness was measured following ASTM D-4366-84, and tensilestrength and elongation were measured following ASTM D 2370-92.

EXAMPLES Example 1 Formation of Urethane Oligomer

[0074] Initially, a 254.48 g quantity of toluene diisocyanate (TDI) anda 320 g quantity of methyl ethyl ketone (MEK) were placed in a glassreaction flask. The TDI and MEK were bathed continuously with an inertnitrogen atmosphere while being stirred gently in the flask. Thereaction flask was gently heated to a temperature of 140° F. At atemperature of about 125° F., 34.84 g of solid2-ethyl-2-(hydroxymethyl)-1,3-propanediol (TMP) were added to thereaction flask. After addition of the TMP, 434.2 g of polytetramethyleneglycol (PM-650) (average molecular weight 672 for the particular lot)were added gradually to the reaction flask with an addition funnel.

[0075] With the addition of the TMP and PM-650, the exothermicity of thereaction required cooling of the flask to maintain the flask at thedesired reaction temperature of about 140° F. Upon completion of theaddition of the PM-650, the glass addition funnel was rinsed with 50 gof MEK, which was then added to the reaction flask. When the temperaturedropped below 140° F., the flask was heated to maintain the temperaturenear 140° F. The reaction was continued at or near 140° F. for about 4-6hours for completion of the prepolymer reaction.

[0076] Toluene diisocyanate (TDI) has two functional isocyanate groupsyielding an equivalent weight of 87 based on a molecular weight of 174.TMP has three hydroxy groups corresponding to an equivalent weight ofabout 44.67. PM-650 has two hydroxy groups corresponding to anequivalent weight of about 334. Based on the quantities added above andthe noted equivalent weights, the equivalents of TDI, TMP and PM-650added were, respectively, 2.925, 0.780 and 1.3. This corresponds torelative equivalents of TDI:TMP:PM-650 of 2.25:0.60:1.00.

[0077] The MEK (370 g) was the only significant volatile component ofthe composition. A total of 1093.52 g of urethane oligomer solution wasrecovered. The remaining compounds (theoretically 723.52 g) werenon-volatile. The weight percentage of the non-volatile components basedon the theoretical estimate was 723.52/1093.52=66.16%. The weightpercentage of the non-volatile component as determined with the methodof ASTM D 2369-90 was 66.97%. The remaining, unreacted NCO functionalgroups were evaluated according to ASTM procedure ASTM D-1638-74,sections 86-92. In this procedure, to determine the number of NCOfunctional groups (i.e., amine equivalent), excess di-n-butylamine wasadded to form a urea by reaction with the isocyanate groups. Thequantity of excess amine was determined by titration with a standardsolution of hydrochloric acid. The NCO or amine equivalent can bedefined as the weight of sample that reacts with one equivalent ofdibutylamine. The oligomer equivalent weight was determined by dividing100×equivalent weight NCO by the percent NCO.

[0078] For the above sample, the percent NCO as a portion of solids was5.09%. Estimating the percent NCO using the quantities of material addedand assume complete reaction yields 5.16%. The percent NCO as a portionof solution was 3.41%. The oligomer of the sample had an equivalentweight of (42.02×100)/3.41=1232 g/eq.

[0079] The representative procedure of Example 1 was repeated for theformation of additional urethane oligomers. The reactants andcharacteristics of these other urethane oligomers are tabulated inTable 1. TABLE 1 Urethane Oligomers UO ID TDI/TMP/DIOL NCO-EW NCO-EW No.(by equivalence) NCO/OH DIOL (Solu.) (Solids) 1 2.0/0.0/1.0 2.00 PM-650  895.9 610 2 2.0/0.0/1.0 2.00 KB-320 630 323 3 3.0/0.0/1.0 3.00 PM-650424 252 4 2.25/0.0/1.0 2.25 PG-55 643 369 5 2.5/0.0/1.0 2.50 PG-55 609310 6 2.8/0.3/1.0 2.15 PM-650 652 371 7 2.55/0.3/1.0 1.96 PM-650 703 4518 2.3/0.3/1.0 1.77 PM-650 834 557 9 2.55/0.6/.7 1.96 PG-55 576 366 10 2.3/0.3/1.0 1.77 PG-55 788 523 11  2.55/0.5/.8 1.96 PM-650 634 405 12 2.55/0.3/1.0 1.96 PG-55 632 416 13  2.55/0.4/1.1 1.70 PM-650 849 565 14 2.25*/0.25/1.0 1.8  PM-650 886 592 15  2.25*/0.14/1.0 1.97 PM-650 791523 16  2.25**/0/1.0 2.25 PM-650 834 528

Example 2 Preparation of Ketimine

[0080] A ketimine was formed to later react with the isocyanatefunctionalized urethane oligomer. To form the ketimine, 92.81 g ofaminoethyl piperazine (AEP) and 207.19 g of MEK were added to a flaskand left to react for a couple of hours.

[0081] AEP has one functional primary amine for an equivalent weight of129. Similarly, MEK has one equivalent per molecular for an equivalentweight of 72. It follows that a significant excess of MEK was added toreduce the amount of unreacted AEP In particular, a three fold excess byequivalence of MEK was added. The product was analyzed by gaschromatography. From GC analysis, the ratios of equivalents of ketimineto AEP (unreacted) was 95/5.

[0082] If all of the AEP reacted to form ketimine, 417 g of thecomposition (including solvent) would correspond to 1 equivalent, andthe equivalent weight would be 417 g. Any unreacted AEP, however, hastwo equivalents per molecule since it can react with an isocyanate atboth the primary amine and the secondary amine. Assuming that 95 percentof the AEP has formed ketimine, 5 percent remains as unreacted AEP.Similarly, with 417 g corresponding to about 1.05 equivalents, theequivalent weight was about 399.

Example 3 Formation of Ketimine Terminated Urethane Oligomer

[0083] The prepolymer was separated into two equal parts. One part (485g) of the urethane oligomer was added to a glass addition funnel. A147.63 g quantity of ketimine/AEP product was placed into a 2000 mlreaction flask and gently stirred. After a couple of minutes ofstirring, the urethane prepolymer was added to the reaction flask in asteady stream while stirring was continued. The exothermic nature of thereaction resulted in heating of the reaction flask to a temperaturebetween 130° F. and 140° F. during the addition of the urethaneoligomer. As the viscosity of the composition in the reaction flaskincreased during addition of the urethane oligomer, the mixing rate wasincreased to maintain a satisfactory mix rate. The addition of urethaneoligomer was completed after about 5-10 minutes. The addition funnel wasthen rinsed with about 25 ml of MEK, which was subsequently added to thereaction flask. The reaction was terminated following addition of therinse solution.

[0084] The percent non-volatiles was determined by heating a sample orthe reaction product in a dish at 220° F. for one hour. Again using theprocedure of ASTM D 2369-90, from a 0.6965 g portion, 56.86% of thesample remained after heating and from a 0.6552 g sample 56.67%remained. Estimating the percent nonvolatiles based on the quantities ofreactants, assuming complete reaction, yields 56.77%.

Example 4 Formation of Amine-Terminated Urethane Oligomer

[0085] A 655.7 g quantity of the ketimine functionalized urethaneoligomer composition was placed in a flask. Based on the averagenon-volatile content, 372.24 g of material in the flask wasnon-volatile. A 33.50 g quantity of water and 178.68 g quantity ofiso-propyl alcohol were added to the flask. The mixture was stirred forabout 15 minutes to ensure complete mixing. The water hydrolyzed theketimine to remove the ketone protecting group, thereby converting theketimine to an unprotected primary amine.

[0086] The mixture then was placed a rotary evaporation flask forremoval of released MEK by rotary evaporation. The flask was heated to atemperature from about 50° C. to about 55° C. under vacuum for about ahalf hour. A total of 337.85 g of solvent was removed. It is assumedthat essentially all of the methyl ethyl ketone was removed. The initialsolvent removed was 70/30 mixture of MEK/IPA corresponding to theazeotrope.

[0087] The percent non-volatiles (ASTM D 2369-90) in the finalamine-terminated urethane oligomer was determined by placing a two smallsamples (0.8115 g and 07165 g) in a dish and heating to about 220° F.for about 2 hours. The average of the two measurements (72.48% and72.64%) yielded 72.56% non-volatiles.

[0088] The above representative procedure described in Examples 3-4 wasrepeated approximately for the production of other amine-terminatedurethane oligomers. The reactants and characteristics of the resultingoligomers are summarized in Table 2. TABLE 2 Amine-Terminated UrethaneOligomers ATUO UO ID No. ID No. Alcohol/Water Viscosity % Solids  1 150-55% BzOH 59.47  2 2 57% BzOH 68.50  3 3 50% BzOH 60.40  4 4 45% BzOH63.30  5 5 40% BzOH 66.75  6 6 40% BzOH 65.96  7 7 40% BzOH 68.22  8 840% BzOH 63.97  9 9 40% BzOH 68.97 10 10  40% BzOH 67.20 11 11  40% BzOH66.34 12 7 20% BzOH + 20% IPA 66.16 13 7 30% BzOH + 10% IPA 77.47 14 736% BzOH + 4% IPA 74.49 15 7 40% IPA 69.83 16 7 60% IPA 63.48 post add5% AEP + 10% BzOH 17 7 20% BzOH + 20% n-butanol 69.17 post add 5% AEP 187 30% BzOH + 10% n-butanol 67.38 post add 5% AEP 19 1 40% BzOH 67.27 207 45% IPA + 12% water 67.00 21 7 45% IPA + 12% water 66.28 post add 3%IPA + 10% BzOH 22 7 45% IPA + 17% water 72.37 23 7 45% IPA + 13% water24 1 45% IPA + 13% water 68.88 25 12  45% IPA + 13% water 72.91 26 13 47% IPA + 12% water 76.63 27 14  48% IPA + 9% water 16900 77.67 28 15 48% IPA + 9% water 12400 75.86 29 16  60% IPA + 9% water 68.36

Example 5 Copolymer

[0089] The amine-terminated urethane oligomers were ready for mixingwith a epoxy resin, crosslinking agent. The two solutions were pouredtogether and blended with a spatula or the like. The blend was then beapplied as a three mil (wet) film to a glass substrate to determine thebasic properties of the coating. Various blends that were prepared andtheir properties are summarized in Tables 3 and 4. TABLE 3Urethane/Epoxy Copolymers - König Hardness König Hardness Cop ID No.ATUO ID No. BPAGE/Mono Day 1 Day 2 Day 3 Week 2  1  1 85/15 11 24 45  67 2  2 85/15  9 21 43  58  3  3 85/15 21 56 69  97  4  4 85/15 12 17 26 46*  5  5 85/15 16 21 —  74*  6  6 92/8 20 51 74 162  7  7 85/15 22 4271 140  8  7 92/8 20 44 71 153  9  8 85/15 19 36 53 123 10  8 92/8 12 3248 140 11  9 92/8 14 28 45 123 12 10 92/8 11 12 16  65 13  7 85/15 14 2849 137 14  7 85/15 13 30 57 135 15  7 92/8 13 23 41 137 16  7 92/8 13 2341 126 17 11 85/15 14 28 47 138 18 11 92/8 15 29 45 134 19  7 85/15 2348 77 147 20  7 92/8 26 46 78 155 21 13 85/15 38 63 84 144 22 13 92/8 3971 86 148 23 14 85/15 48 77 91 142 24 14 92/8 47 78 92 150 25 15 85/1562 82 95 142 26 15 92/8 59 88 104  152 27 19 92/8 13 24 39 125 28 2092/8 19 30 48 147 29 21 92/8 14 20 35 143 30 22 92/8 73 100  108  154 3124 92/8 60 70 77 139 32 25 92/8 41 51 57 140 33 26 92/8 59 83 98 146 3426 85/15 + 1.7% 55 77 90 136 BzOH 35 27 92/8 40 76 99 134 36 28 92/8 4175 100  137 37 29 92/8 67 89 112  155

[0090] TABLE 4 Urethane/Epoxy Copolymers - Additional Properties Cop IDNo. 2 Wk Taber Tensile Strength % Elong. Range  1 12 3800 5600  2 643000 6300  3 33 2600 4900 10-40   7 49  8 31  9 33 10 28 11 57 12 26 2129 22 26 23 27 24 27 25 31 26 33 30 32 4600 6700 10 31 22 2300 3400 5-1032 33 2200 4800 5-10 33 34 3700 5800 5-10 34 24 3100 5200 10-20  35 4436 39 37 29

Example 6 Systematic Study of Urethane-Epoxy Coating Properties

[0091] In this example, the properties of urethane-epoxy coatingssimilar to those described above are systematically studied. Inparticular, the urethane oligomers are varied along with the relativeamounts of ketimine and epoxy resin.

[0092] The procedures followed to produce these coatings were comparableto those described in the preceding examples. All of the urethaneoligomers were produced using a ratio of 2.25 TDI/1.0 PM-650 byequivalence. The amounts of triol TMP was varied as indicated. Ketiminewas prepared as described in Example 2. The amine terminated urethaneoligomers produced are summarized in Table 5. TABLE 5 ATUO ID-No. TMP(eq) NCO/Ket % NV cps aew (sol'n) 6-1 0.00 0.877 78.44 141,000  442 6-20.00 0.940 73.18 22,700 448 6-3 0.00 1.000 77.84 N/A 376 6-4 0.00 1.06575.11 22,900 370 6-5 0.14 0.877 75.3  75,500 516 6-6 0.14 0.940 72.7650,300 507 6-7 0.14 1.000 72.28 12,700 437 6-8 0.14 1.065 71.24 12,400419 6-9 0.25 0.877 75.73 70,000 506 6-10 0.25 0.940 78.57 103,000  4666-11 0.25 1.000 71.22 25,700 468 6-12 0.25 1.065 73.64 25,200 432 6-130.40 0.877 74.84 107,000  611 6-14 0.40 0.940 72.93 47,400 588 6-15 0.401.000 76.53 58,100 499 6-16 0.40 1.065 70.27 36,600 506 6-17 0.60 0.87774.72 >100,000⁺   759 6-18 0.60 0.940 72.56 118,000  727 6-19 0.60 1.00071.07 65,800 657 6-20 0.60 1.065 69.44 39,100 630

[0093] The amine terminated urethane oligomers were used to produceurethane-epoxy coatings, as described in Example 5. The epoxy resin usedto produce the coating was 95% BPADGE and 5% Epoxide 8 by weight. Theproperties of the resulting coatings are summarized in Table 6. TABLE 6eq NH/ ATUO eq 1 day 2 day 3 day 1 wk 2 wk 1 wk ID-No. epoxy König KönigKönig König König Taber 6-1 0.8 31 43 55 92 125 21 1 51 69 82 116 141 121.2 69 92 106 136 155 14 6-2 0.8 41 56 71 109 139 33 1 62 85 102 137 15512 1.2 81 109 125 156 168 17 6-3 0.8 32 46 92 140 157 27 1 48 76 123 155165 19 1.2 60 92 141 161 168 16 6-4 0.8 40 60 108 147 166 40 1 60 87 136158 171 23 1.2 63 96 146 165 168 15 6-5 0.8 30 46 64 97 125 21 1 22 4275 108 132 22 1.2 57 88 111 139 155 19 6-6 0.8 29 50 72 109 135 29 1 4879 102 135 155 19 1.2 61 96 122 148 165 18 6-7 0.8 43 64 83 126 152 32 158 87 107 146 161 26 1.2 78 108 128 160 175 19 6-8 0.8 42 73 89 134 15944 1 65 100 118 153 168 27 1.2 81 119 134 163 174 21 6-9 0.8 24 38 48 81102 21 1 32 53 67 98 111 12 1.2 48 76 92 120 130 14 6-10 0.8 31 48 60 91115 33 1 29 50 65 106 124 12 1.2 54 90 107 136 145 17 6-11 0.8 46 67 85126 146 30 1 67 95 113 146 158 21 1.2 76 106 123 156 164 18 6-12 0.8 4365 87 126 147 41 1 61 90 109 144 158 26 1.2 72 106 125 151 164 20 6-130.8 18 21 29 44 71 21 1 29 38 51 62 87 22 1.2 35 49 66 76 95 19 6-14 0.822 30 42 58 86 29 1 36 50 68 87 103 19 1.2 38 60 81 96 114 18 6-15 0.834 60 69 105 129 15 1 44 83 92 125 137 17 1.2 47 90 103 132 143 12 6-160.8 38 64 74 111 136 41 1 58 94 104 132 146 23 1.2 69 109 119 146 153 166-17 0.8 26 33 40 52 73 15 1 32 46 55 61 84 13 1.2 39 54 64 78 94 146-18 0.8 29 40 48 63 87 28 1 36 54 65 81 99 17 1.2 48 67 80 94 113 16-19 0.8 39 53 67 92 115 23 1 53 73 87 108 122 19 1.2 58 82 98 120 13015 6-20 0.8 39 51 68 93 114 35 1 54 69 89 112 127 15 1.2 60 85 100 123132 19

[0094] The embodiments described above are intended to be representativeand not limiting. Additional embodiments of the invention are within theclaims.

What is claimed is:
 1. A composition comprising greater than about 55percent by weight amine-terminated urethane oligomers.
 2. Thecomposition of claim 1 wherein the composition comprises from about 60percent to about 90 percent by weight amine-terminated urethaneoligomers.
 3. The composition of claim 1 wherein the compositioncomprises from about 65 percent to about 80 percent by weightamine-terminated urethane oligomers.
 4. The composition of claim 1further comprising an aqueous viscosity modifying agent.
 5. Thecomposition of claim 4 wherein said aqueous viscosity modifying agentcomprises greater than about 30 percent by weight volatile alcohol. 6.The composition of claim 1 further comprising volatile organic acids,said composition comprising less than about 10 percent by moleequivalent of carboxylate groups of said volatile organic acids relativeto amine groups of said amine-terminated urethane oligomers.
 7. Thecomposition of claim 1 further comprising volatile organic acids, saidcomposition comprising less than about 1 percent by mole equivalent ofcarboxylate groups of said volatile organic acids relative to aminegroups of said amine-terminated urethane oligomers.
 8. The compositionof claim 1 wherein said amine-terminated urethane oligomers compriseprimary amine-terminated oligomers
 9. The composition of claim 1 whereinsaid amine-terminated urethane oligomers comprise multifunctional aminemoieties bonded at secondary amine sites to isocyanate functional groupsof a urethane oligomer to form carbamate linkages.
 10. The compositionof claim 9 wherein said multifunctional amine moieties compriseN-(aminoethyl) piperazine moieties.
 11. A kit comprising: a) acomposition comprising greater than about 55 percent by weightamine-terminated urethane oligomers; and b) a polyepoxide compound in acontainer separate from said composition comprising amine-terminatedurethane oligomers.
 12. The kit of claim 11 wherein said polyepoxide isa polyglycidyl ether of a polyphenol, a polyglycidyl ether of aliphaticpolyol with 2 to 4 hydroxyl groups, or mixtures thereof.
 13. The kit ofclaim 11 wherein the ratio of active hydrogens in amine functionalgroups to epoxide groups ranges from about 1:1 to about 1.75:1.
 14. Amethod of producing an amine-terminated urethane oligomer compositioncomprising the steps of a) adding water to a polyketimine functionalizedurethane oligomer; and b) removing ketone to form a compositioncomprising greater than about 55 percent by weight amine-terminatedurethane oligomer.
 15. A polymer coating comprising an epoxy crosslinkedamine-terminated urethane polymer, said coating formed by curing amixture of polyepoxides and a composition comprising greater than about55 percent by weight amine-terminated urethane oligomers.
 16. A methodof forming a coating comprising the steps of spreading a mixture on asurface such that it can cure, the mixture being obtained by mixingpolyepoxides with a composition comprising greater than about 55 percentby weight amine-terminated urethane oligomers
 17. The method of claim 16wherein said surface comprises concrete.
 18. The method of claim 16wherein said surface is a floor or a wall.